All of the material in this patent application is subject to copyright protection under the copyright laws of the United States and of other countries. As of the first effective filing date of the present application, this material is protected as unpublished material. However, permission to copy this material is hereby granted to the extent that the copyright owner has no objection to the facsimile reproduction by anyone of the patent documentation or patent disclosure, as it appears in the United States Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
Not Applicable
1. Field of the Invention
This invention pertains to selling of digital content over a computer network. More particularly the invention pertains to a system which ensures more reliable delivery of digital content via a computer network.
2. Background of the Invention
In the past few years there has been an immense increase in the volume of sales transactions conducted over the Internet. A large portion of the sales, are of physical tangible goods, that must be shipped via conventional means after an order is accepted via the Internet.
Another class of goods which may be offered for sale over the Internet is digital content. Digital content comprises computer files that have some monetary value. Examples of digital content include computer programs (e.g., accounting software, database software, data files, and multimedia material (e.g., digital audio files, digital video files)). In the case of digital content there is the possibility to complete the entire transaction, i.e., accept payment from a customer, and deliver the digital content to the customer, within the confines of the computer network (e.g., Internet).
The file transfer protocol (FTP) provides a flexible and reliable method to transfer files over the Internet. Usual implementations of this protocol provide a means for limiting access to FTP servers based username/password credentials, and some xe2x80x9canonymous FTPxe2x80x9d enabled implementations of the protocol allow anyone unfettered access to the FTP server. The latter only require an email address, which no steps are taken to verify, to be entered as the password. Such email addresses are merely to be used for informational purposes by the system administrator. FTP systems commonly provide a method for recovery from a data transmission fault that does not entail retransmitting the entire file. This is especially useful in the case of large files. The FTP systems described, do not function to limit access to digital content to purchasers who have payed for them.
The Open Market Corporation provides a Hypertext Transfer Protocol (HTTP) based system which is useful for limiting access to certain files to paying customers. The system works as follows. A customer clicks on a product xe2x80x9cBuy Buttonxe2x80x9d in a World Wide Web (WWW), Hypertext Markup Language (HTML) document. The xe2x80x9cBuy Buttonxe2x80x9d points to cash register Common Gateway Interface (CGI) program, which presents a HTML form to the user for the purpose of accepting payment information. The customer then enters payment information, e.g. credit card information, and submits the form to by clicking on the submit button. The targeted cash register then verifies the payment information. If the payment information is accepted, the cash register program generates a special Uniform Resource Locator (URL) with appended data called a digital receipt which points to a digital receipt verification CGI program. The cash register then formats the digital receipt into a WWW page, and sends the WWW page to the user. When the user clicks on the link referencing the digital receipt URL the digital receipt is sent to the verification program which checks the digital receipt, and if it is found valid, generates a web page comprising a link to the purchased digital content. The user may then download or view the purchased digital content by clicking on the link to it. The digital receipt data may include an expiration date, or a limit on the number of downloads.
The Open Market system employs the HTTP protocol for communication and consequently suffers from certain limitations inherent to that protocol which make it less than ideally suited to the purpose of transferring purchased digital content. The HTTP protocol provides a communication model comprising a request from the client to the server for a resource indicated in a URL and a response transmitting the resource. There is no provision for a response to the response. The purchase of digital content being a business transaction can benefit from further communication to notify the seller that the buyer is satisfied with the purchased item.
Another shortcoming of the Open Market system is that it does not provide a means for verifying the content of the received digital content other than that provided in the lower levels of the communication protocol stack e.g. (TCP error correction). The user may not become aware of data errors until the file is accessed, at which time, the web browser loaded with the WWW page containing the digital receipt will have been closed and/or the digital receipt will have expired or the limit on downloads met.
Another shortcoming of the Open Market system resulting from its reliance on HTTP is that it does not provide a method for recovery for gross communication errors e.g. network errors which temporarily sever the client server communication link. In the case the download of the digital content is interrupted for some reason, e.g. due to a communication error, the digital content download will have to be restarted from the beginning. This can be particularly troublesome in the case of large multimedia files e.g. video files, which involve long downloads that tie up the user""s computer.
Accordingly what is needed is a system and method which overcomes the abovementioned shortcomings, and more particularly which provides access for buyers to purchased digital content, that provides for verification of the integrity of the digital content, and communication between the client and the server as to the outcome of the verification.
What is further needed is a method for transmitting a digital content item between a client and a server that includes error recovery and avoids the necessity of retransmitting an entire file in the event of a communication error.
A method for transporting a digital content item between an order fulfillment server and a client computer, the method comprising steps of accepting a digital receipt from a user, presenting a choice of digital content for which the digital receipt is valid, accepting a request for a digital content item from the user, computing a first checksum of the digital content item at the order fulfillment server, transmitting the digital content item from the order fulfillment server to the client computer using a protocol capable or recovering from communication errors without the need to retransmit the entire digital content item, computing a second checksum of the digital content item at the client computer, and comparing the first checksum to the second checksum.
According to another aspect of the invention a system and computer readable medium is disclosed for carrying out the above method.